AZTECS (from the Nahuatl word aztlan, "place of the Heron," or "Heron" people), the native name of one of the tribes that occupied the tableland of Mexico on the arrival of the Spaniards in America. It has been very frequently employed as equivalent to the collective national title of Nahuatlecas or Mexicans. The Aztecs came, according to native tradition, from a country to which they gave the name of Aztlan, usually supposed to lie towards the north-west, but the satisfactory localization of it is one of the greatest difficulties in Mexican history. The date of the exodus from Aztlan is equally undetermined, being fixed by various authorities in the 11th and by others in the 12th century. One Mexican manuscript gives a date equivalent to A.D. 1164. They gradually increased their influence among other tribes, until, by union with the Toltecs, who occupied the tableland before them, they extended their empire to an area of from 18,000 to 20,000 square leagues. The researches of Humboldt gave the first clear insight into the early periods of their history. See Mexico; Nahuatlan Stock.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)